This invention relates generally to apparatus for dispensing liquids. More particularly, it relates to apparatus used in connection with liquid dispensing pumps, which pumps include replaceable filtering elements. Even more particularly, this invention relates to apparatus for preventing spillage of liquids from such pumps during the changing of a filtering element attached to such pump.
In many dispensing pumps, particularly those used for dispensing gasoline, it is now common practice to include replaceable filter elements. These filter elements conventionally are located on the side of the pumping apparatus and must be changed periodically to maintain proper filtering protection. The filtering elements conventionally are removably attached to a mount extending out from the side of such a pump and may be attached to such mount either by screw threads or by clamps.
To protect the purity of the liquid dispensed by the pump, it is necessary that the filtering element be replaced at periodic intervals. Some liquids dispensed by such pump present sufficient potential danger either to safety or to the environment that they must be contained and spillage prevented. One example of this requirement is with gasoline pumps, where substantial spillage may pose both an environmental hazard and a potential fire hazard. In several known instances pumps dispensing such liquids have experienced major spills during the time that the filtering elements were being changed on the pumps. This can occur when the pumps are inadvertently activated at a time that a filter element is not in place or simply by the liquid contained within the filter element itself. Such dangers have prompted a search for means to prevent such unintentional spillage and the dangers that it presents.